JPH05222408A - Extrusion molding method for powder material and device therefor - Google Patents

Abstract

PURPOSE:To reduce the cost of production and widen the application range of a powder material by enabling easy extrusion molding of the powder material to be used for general powder metallurgical processing (die compression molding methods). CONSTITUTION:This process consists of a setting stage in which the powder material A is packed into a cavity 1 formed of the through-hole of a container 2 as an outer periphery and the upper surface B1 of an in-progress molding B before being pushed into the through-hole including the narrow part 3b of a die 3 as a base, a pressurizing stage in which a punch 5 descends to pressurize the powder material A while fitting into the through-hole of the container 2 and the powder material A is thereby pressed downward and is pushed into the through-hole including the narrow part 3b of the die 3 so as to be worked to the next in-progress molding B and simultaneously, the previous in-progress molding forming the base of the cavity 1 thus far is pushed by the above-mentioned next in-progress molding B into the narrow part 3b until the molding completely passes the narrow part and is extruded into the through-hole of a die block 4 and a detaching stage in which the extrusion molding is taken out of the inside of the die block 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method of extrusion molding a powder material and its apparatus.

[0002]

2. Description of the Related Art In the case of a die compression molding method, there is a limit to applying a uniform pressure to a powder material if the length is longer than the sectional area such as a rod or a tube. In such cases,
Conventionally, an extrusion molding method of a powder material has been adopted.
In this extrusion molding method, usually, a binder such as a wax is added to give a plasticity to the powder material to form a paste, which is filled in a die of an extruder similar to injection molding and pressure is applied, Extrude through the holes in the mold. Often, the extruded product is used as a binder to remove the substance used as a binder in a later step by dewaxing or the like. In the high temperature extrusion, since the powder material is restricted in terms of material and temperature so as not to be oxidized, for example, the canning method may be applied to a powder material which may be oxidized at a high temperature. In this method, the material is put in a can, vacuum is drawn, and the hermetically sealed product is extruded. After molding, except in a special case, the pod of the can material is chemically dissolved and removed.

[0003]

The conventional extrusion molding method requires many complicated auxiliary steps such as a pretreatment step for imparting a predetermined plasticity to the powder material and a posttreatment step such as dewaxing after molding. Therefore, it is disadvantageous in terms of manufacturing cost. This is even more so in hot extrusion. Therefore, the application of the extrusion molding method is high in added value due to its economical efficiency, and is limited to special powder materials and molded bodies that cannot obtain the same properties as those after extrusion molding by a general powder metallurgy method or the like. The present situation is that it is not a general molding method for mechanical structural parts despite its excellent properties.

The present invention has been made in view of such a background, and makes it possible to easily extrude a powder material used in a general powder metallurgy method (mold compression molding method), thereby reducing the manufacturing cost. An object of the present invention is to provide an extrusion molding method of powder material and an apparatus thereof, which can expand its application range.

[0005]

In order to achieve the above object, in the extrusion molding method of powder material according to the present invention, as described in claim 1, the through hole of the container is used as the outer circumference, and the die is pinched. The step of filling the powder material into the cavity formed with the upper surface of the intermediate molded body before being pressed into the through hole including the part as the bottom surface, and the punch descends to fit into the through hole of the container. While pressing the powder material while pressing the powder material downward, the powder material is pressed into the through hole including the constricted portion of the die to be processed into the next formed body, and at the same time, the bottom surface of the cavity is formed. A pressurizing step of pushing an intermediate molded body into the constriction portion by the next intermediate molded body and completely extruding it into the through hole of the die block, and a releasing step of taking out the extruded molded body from the die block. When Ranaru made. Further, the application device includes a container having a through hole, a die holding the container and having a constricting portion formed in the through hole in a shape corresponding to a molded body, and holding and sandwiching the die. A die block capable of accommodating the extruded body that has completely passed through the constricted portion is closely arranged on the coaxial line with a die block that can be raised and lowered on the axis of the container and fitted into the through hole of the container. A cavity for forming a cavity having a through hole of the container as an outer periphery and a bottom surface of which is an upper surface of the intermediate molded body before being pressed into the through hole including the constricted portion of the die. The powder material is filled in the inside, and the punch is lowered to press the powder material while fitting into the through hole of the container, thereby pressing the powder material downward and including the constricted portion of the die. Push in To form the next intermediate molded body, and at the same time, the former intermediate molded body that has formed the bottom surface of the cavity is pushed into the constriction portion by the next intermediate molded body and completely passes through this to be processed into an extruded molded body. The point is to do.

[0006]

According to the present invention described above, a cavity having the through hole of the container as the inner wall and the upper surface of the pre-extruded molded body in the die as the bottom surface is formed, and the cavity is filled with the powder material. Then, the punch press-fits into the cavity to press the powder material in the cavity while the powder material in the cavity is being pressed and the intermediate compact before the bottom surface of the cavity is formed. The former intermediate molded body is pushed into the constricted portion in the die and completely passes therethrough to become an extruded molded body. In this method, the volume of the powder material filled in the cavity is compressed and reduced sequentially in the direction perpendicular to the axis, and the powder material is extruded while increasing from the packing density to the molding density.

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of an apparatus for carrying out the extrusion molding method according to the present invention, and FIG. 3 shows an extrusion molded body produced by the apparatus. In addition, FIG. 1 shows an apparatus configuration in a state where the powder material A is filled. FIG. 2 shows the configuration of the apparatus in the extrusion process, the left side shows the state in the middle of extrusion, and the right side shows the state after the completion of extrusion. The extrusion molding apparatus shown in FIG. 1 includes a container 2, a die 3 disposed under the container 2 to confine the powder material A and substantially perform extrusion molding, and a molded body C extruded while holding the die 3. And a die block 4 capable of accommodating a die, and a punch 5 as an extruding means.

The container 2 has through holes of a predetermined size formed in the upper and lower portions of the central portion, and the through holes form a cavity 1 with the upper surface B1 of the intermediate molded body B as described later. The die 3 has a through hole arranged coaxially with the cavity 1. This through hole has an opening-side portion 3a on the upper side that is substantially the same as the hole diameter of the cavity 1, and a lower portion adjacent to this portion 3a is inclined such that the diameter is smaller than the hole diameter of the portion 3a. The diameter portion becomes the constricted portion 3b having the target shape to be molded. The constricted portion 3b here has a hole diameter that substantially matches the outer diameter L1 of the molded body C of FIG. Die block 4
It is formed in a tubular shape having an inner diameter in which the molded body C is housed. The die block 4 has an outer periphery provided with an opening 4a through which the molded body is taken out and a locking groove 4b is formed at the lower end of the outer periphery.
Is provided.

The container 2, the die 3, and the die block 4 described above are coaxially installed in the cylinder of the die holder 6.
The die holder 6 includes a mounting flange 6a provided on the lower end of the outer periphery, an opening 6b provided on the lower side of the outer periphery and overlapping with the opening 4a, and an engagement groove provided on the lower end of the inner periphery and opposed to the engagement groove 4b. 6c and the container 2 provided at the upper end of the inner circumference
6d that engages with the small diameter step 2a at the outer peripheral tip of
And have integrally. In the cylinder of the die holder 6, first, the container 2 and the die 3 are sequentially inserted from the lower side, and then the die block 4 is inserted. The die block 4 is positioned, and the common lock pin 7 is press-fitted into the locking grooves 4b and 6c. Then, when the container 2 is moved upward, the step 2a,
The upper ends of the containers 2 are flush with the upper ends of the die holders 6 due to the engagement of the 6d. The die 3 is fixedly held between the container 2 and the die block 4 fixed by the lock pin 7. The die holder 6 is fixed on the lower hard plate 8 by the bolt 9 in this assembled state.

Further, the punch 5 has an upper hard plate 10
It is fixed via a stopper ring 11 and is moved up and down by a driving force such as a hydraulic press connected to the upper hard plate 10. Stopper ring 11 is bolt 12
Is fixed to the upper hard plate 10, and the punch 5 is projected downward from the center hole thereof. Then, after the punch 5 moves up to the maximum, it stands by at a fixed position on the axis coaxially with the container 2.
As shown on the right side of FIG. 2, the lowermost position is restricted to a position where the lower surface 11a of the stopper ring 11 contacts the upper surface of the container 2.

Next, as shown in FIG.
The procedure for producing the columnar extruded body C shown in FIG. Here, the cavity 1 has a through hole of the container 2 as the outer periphery as shown in FIG. 1, and the intermediate molding before being pushed into the through hole including the constricted portion 3b of the die 3 by lowering the punch 5 as shown in the right side of FIG. The upper surface B1 of the body B is formed as the bottom surface, and the powder material A is filled therein. During this filling operation, the punch 5 stands by at a fixed position on the shaft.

Then, the punch 5 descends before and after the completion of filling. The punch 5 descends as shown in the left side of FIG. Then, the powder material A in the cavity 1 is pressed downward and the die 3
Is pressed into the through hole including the constricted portion 3b, and the intermediate molded body B is formed as shown from the left side to the right side in FIG. At the same time,
The intermediate molded body B before forming the bottom surface of the cavity 1 is completely pushed into the constricted portion 3b and passes therethrough to form the molded body C.
Then, the molded body C is extruded from the die 3 into the die block 4 by the next intermediate molded body B which is further pressed. The punch 5 is prevented from descending by the stopper ring 11 contacting the container 12.
At this time, the tip of the punch 5 has a narrowed portion 3b as shown in the right side of FIG.
It is located directly above and at the boundary between the container 2 and the die 3.

Therefore, when the punch 5 is lifted from this state and separated from the container 2, as shown in FIG.
The upper surface B of the intermediate molded body B in the through hole of the die 3 including
The aforementioned cavity 1 having the bottom surface 1 is formed. Further, the molded body C extruded into the die block 4 has the opening 4
It can be easily taken out from the die block 4 through a and 6b. By repeating the above operation, the molded body C by extrusion can be continuously processed. In this extrusion molding method, while the punch 5 is pushed into the cavity 1 to reduce the volume of the cavity 1, the volume reduction amount of the powder material A depends on the inner diameter of the constriction portion 3b, which is filled with the powder material A. It is determined by design based on the relationship between the apparent density and the molding density. Therefore, it is easy to mold the powder material A to a required density, and the apparatus configuration may be modified by designing the compression molding mold to some extent.

FIG. 4 shows a second embodiment of the present invention.
The second embodiment is an example of producing the cylindrical extruded body E shown in FIG. 6 by applying the method of the present invention. 4 shows the apparatus configuration, the left side of the figure shows a state in which the powder material A is filled, and the right side of the figure shows a state after the extrusion is completed. The extrusion molding method of the second embodiment is different from the extrusion molding method of the first embodiment in that the powder material A can be filled in a cylindrical shape, and the powder material A can be pushed into the constricted portion while remaining in a cylindrical shape to increase the volume. Ingenuity has been made in the decreasing structure and the separating structure of the molded body E. The molding device used is a container 22 and a container 22.
A die 23 arranged below the die 23, a die block 24 for holding the die 23, a mandrel 25 and the like constitute a main part of the die, and a punch 35 as an extruding means.
Is equipped with.

The container 22 has through holes of a predetermined size formed in the upper and lower portions of the central portion thereof, and the through holes, together with the upper surface D1 of the intermediate compact D and the mandrel 25, form the cavity 2 as described later.
1 is formed. The die 23 has a through hole coaxial with the cavity 21. The through hole has an upper opening near the opening, and the lower opening adjacent to this opening is inclined so as to have a smaller diameter than that of the opening. Becomes a constricted portion 23b having a non-target shape to be molded. The constricted portion 23b here has a hole diameter that substantially matches the outer diameter L2 of the molded body E of FIG. The die block 24 is formed in a cylindrical shape having an inner diameter in which the molded body E is stored. The mandrel 25 has the same length as the stacked length of the container 22, the die 23, and the die block 24. Further, the mandrel 25 is inserted into the through holes of the container 22, the die 23, and the die block 24,
The portion located inside the die 23 has a larger diameter than the other portions, and further, the maximum diameter portion is inclined so as to be large in diameter against the constricted portion 23b, and the maximum diameter portion is the target inner shape to be formed. Has an inner diameter constricted portion 25a. The inner diameter constricted portion 25a here has an outer diameter substantially matching the inner diameter L3 of the molded body E.

The above container 22, die 23, and die block 24 are coaxially installed in the cylinder of the die holder 26. The die holder 26 includes a flange portion 26a provided at the outer peripheral upper end portion, bushes 27 provided at a plurality of positions of the flange portion 26a, and a small diameter step portion of the outer peripheral lower end portion of the die block 24 provided at the inner peripheral lower end portion. And a step portion 26b that engages with. After the die block 24, the die 23, and the container 22 are sequentially inserted into the die holder 26 from the upper side, the circular groove provided on the upper end surface of the die holder 26 and the container 22 so as to oppose it.
The pressing ring 28 arranged in the circumferential groove provided in the above is mounted by bolts 29 to fix the above three parts. The die holder 26 described above is supported by a plurality of headed guide lots 30 standing on the lower hard plate 8 so as to be vertically movable via bushes 27, and is arranged around the axis of the guide rod 30. It is urged upward by the compression spring 31 and is normally in the upper position maintaining a predetermined distance from the lower hard plate 8.

The punch 35 has a cylindrical shape having an inner diameter 35a corresponding to the mandrel 25, is fixed to the upper hard plate 10 via a stopper ring 11, and is moved up and down in conjunction with the upper hard plate 10. The stopper ring 11 is fixed to the upper hard plate 10 with bolts 12, and the punch 35 projects downward from the center hole thereof. After the punch 35 is raised to the maximum, it waits at a fixed position on the shaft coaxially with the container 22. When the punch 35 is lowered, the die holder 26 is lowered along the guide rod 30 to the upper surface of the container 22 as shown on the right side of FIG. Lower surface 11 of stopper ring 11
a is abutted, and the lower end surface of the die block 24 is abutted against the lower hard plate 8.

Next, the procedure for producing the extruded compact E by the above extrusion molding device will be described. here,
The cavity 21 is formed with the through hole of the container 22 as the outer circumference, the outer circumference of the mandrel 25 as the inner circumference, and the upper surface D1 of the intermediate molded body D before being pressed into the through hole of the die 33 as the bottom surface as shown on the left side of FIG. Then, the powder material A is filled therein. During this filling operation, the punch 35 stands by at a fixed position on the shaft.

Then, before and after the completion of filling, the punch 35 is used.
Goes down. Then, after the punch 35 descends to the container 22, the die holder 26 starts descending along the guide lot 30 against the biasing force of the compression spring 31. When the die holder 26 starts descending, the punch 35 moves to the container 22.
It is fitted into the cavity 21 between the through hole and the mandrel 25 and descends to compress the powder material A and extrude the former intermediate compact D into the die block 24. The compression and extrusion process is basically the same as the first embodiment. Then, when the punch 35 reaches the lowest position, the lower end of the punch 35 is located right above the constriction portion 23b and the inner diameter constriction portion 25a, and is located at the boundary between the container 22 and the die 23.

Therefore, the die holder 26 is returned to the original position along the guide rod 30 by the urging force of the compression spring 31 while the punch 35 is raised from this state to the home position. As shown in the left side of FIG.
3b, the above-mentioned cavity 21 is formed in the through hole of the die 23 including the inner diameter constricted portion 25a with the upper surface D1 of the intermediate molded body D as the bottom surface. Further, the extruded molded body E is
It remains under the raised die block 24 and can be easily taken out. By repeating the above operation, the molded body E by extrusion can be continuously processed.
Also in this extrusion molding method, the volume reduction amount of the powder material A filled in the cavity 21 depends on the interval between the constriction portion 23b and the inner diameter constriction portion 25a, which is the apparent density and the molding density when the powder material A is filled. It is decided by design in relation to. In addition,
In the second embodiment, the extruded molded body E has been described as a cylindrical shape, but a rectangular tube can be molded by the same device.

Next, a third embodiment of the present invention will be described. The third embodiment is an example of manufacturing a molded body G having oblique teeth on the outer peripheral portion as shown in FIG. 7 by the extrusion molding method of the present invention. Note that FIG. 5 shows the apparatus configuration, the left side of the figure shows a state in which the powder material A is filled, the right side of the figure shows a state at the time of completion of extrusion, and the same site as the apparatus configuration of the first and second examples is shown. The same reference numerals are given, and only the main configuration will be described in detail.

The molding apparatus of the third embodiment is different from the molding apparatus of the second embodiment in that the constricted portion 43b provided in the die 23 is the target shape to be molded, that is, the oblique tooth shape of the molded body G in FIG. And the lower portion 43c following the constricted portion 43b also has a continuous oblique tooth shape. The inner diameter constricted portion 45a with respect to the target inner shape has an outer diameter that is substantially the same as the inner diameter L4 of the molded body G. In addition, an optional rotation mechanism is provided in the main part. As the rotating mechanism, in the case of the die block 44, the block is vertically divided into two and a roller bearing 46 is interposed therebetween, and in the case of the punch 35, a pair of bearing receivers 47 is provided between the block and the upper hard plate 10. Although the roller bearing 48 is interposed between these rollers, another rotation mechanism may be used.

With the above structure, the powder material A filled in the cavity 21 is first pushed into the gap between the constriction portion 43b and the inner diameter constriction portion 45a to become the intermediate compact F.
By completely passing through this, it is extruded into the shape shown in FIG. In the molding process, since the requirements of the present invention are provided in addition to the rotation mechanism, the material flow smoothly to the helical tooth shape with high resistance, and the powder material A increases from the packing density to the molding density. It is extruded into a molded body G as designed. In addition, in the third embodiment, the molded body G having the helical teeth on the outer peripheral portion has been described. For example, in the case of the molded body having the helical teeth in the inner hole, a rotating mechanism may be attached to the lower part of the mandrel. This will be possible. in this way,
The present invention can be variously modified or expanded within the scope described in the claims.

[0024]

As is apparent from the above description, the extrusion molding method of the powder material according to the present invention is capable of easily extruding the powder material used in the general powder metallurgy method and increasing the packing density from the packing density to the molding density. An extruded body having a shape corresponding to the narrowed portion can be obtained. Further, in the molding apparatus of the present invention, the extrusion molding method of the method of the present invention can be carried out by simply making some design changes to the conventional mold compression apparatus, and since the continuous processing can be performed, the productivity is good, Industrial mass production becomes possible. This allows the present invention to extend the range of applications for extrusion of powder materials.

[Brief description of drawings]

FIG. 1 is a molding apparatus as a first embodiment of the present invention,
It is sectional drawing shown in the state at the time of completion of powder material filling at the time of extrusion-molding a powder material into a cylinder.

FIG. 2 is a cross-sectional view showing the molding apparatus in a state during extrusion and at the time of completion of extrusion.

FIG. 3 is a perspective view of an extrusion molded body obtained by the molding apparatus.

FIG. 4 is a molding apparatus as a second embodiment of the present invention,
FIG. 4 is a cross-sectional view showing the same apparatus when the powder material is filled and when the molded body is completely taken out.

FIG. 5 is a cross-sectional view showing an apparatus as a third embodiment of the present invention, showing the apparatus in a state at the time of filling powder material and at the time of completion of taking out a molded body.

FIG. 6 is a perspective view of an extrusion molded body obtained by the molding apparatus of the second embodiment.

FIG. 7 is a perspective view of an extrusion-molded body obtained by the molding apparatus of the third embodiment.

[Explanation of symbols]

 1, 21 Cavities 2, 22 Containers 3, 23 Dies 4, 24, 44 Die blocks 3b, 23b, 43b Dies side constrictions 25a, 45a Mandrel side inner diameter constrictions 5, 35 Punches A Powder materials B, D , F Mid-stage compact C, E, G Extruded compact

Claims (2)

[Claims] 1. A container having a through hole, a die having a constricted portion formed in the through hole in a shape corresponding to the molded body, and an extruded molded body completely passing through the constricted portion. A die block that can be housed in a hole is closely arranged on a coaxial line, and a punching device that is installed vertically on the axis of the container and is fitted and inserted into a through hole of the container is used. A setting step of filling a powder material into a cavity formed by using the through hole of the container as an outer periphery and the upper surface of the intermediate molded body before being pressed into the through hole including the constricted portion of the die as a bottom surface, By pressing the powder material while the punch descends and fits in the through hole of the container, the powder material is pressed downward to be pushed into the through hole including the constricted portion of the die and the next intermediate compact Processed into At the same time, a pressurizing step of pressing the intermediate molded body before forming the bottom surface of the cavity into the constriction portion by the next intermediate molded body and completely passing therethrough and extruding into the through hole of the die block, An extrusion molding method for a powder material, which comprises a step of removing the extrusion molded body from the die block. 2. The extrusion of a powder material to be filled in a cavity of a mold, the density of which is increased from a packing density to a molding density in a process of extruding from the cavity to the outside of the mold, and which is molded into an extrusion molded body having a predetermined shape. In a molding apparatus, a container having a through hole, a die holding the container and having a constriction portion formed in the through hole in a shape corresponding to a molded body, and holding the die to constrict the constriction portion. The extrusion molded body that has completely passed through is closely arranged on a coaxial line with a die block that can be housed in the through hole, and is installed so as to be able to move up and down on the axis of the container, and is fitted and inserted into the through hole of the container. A punch, and forming a cavity having a through hole of the container as an outer periphery and a top surface of an intermediate molded body before being pressed into the through hole including a constricted portion of the die as a bottom surface, The powder material is filled in Yabitei,
By pressing the powder material while the punch descends and fits into the through hole of the container, the powder material is pressed downward to be pushed into the through hole including the constricted portion of the die and the next intermediate molding is performed. Characterized in that it is processed into a body, and at the same time, the former intermediate molded body that has formed the bottom surface of the cavity is pushed into the constricted portion by the next intermediate molded body and completely passes therethrough to be processed into an extruded molded body. Extruder for powder material.